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1. A 20 N horizontal force is applied to a 4.0 kg box. The box moves a horizontal distance of 3.0 meters. The work done by the 20 N forces is...?

1. 60 J

2. 80 J

3. 100 J

4. 120 J

5. 140 J

2. A roller coaster is towed up an incline at a stable speed of 0.50m/s by a chain parallel to the surface of the incline. The slope is 3.0 percent, which means that the elevation increases by 3 m for every 100 m of distance along the surface. The mass of the roller coaster is 400 kg. Neglect friction, what is the magnitude of the force exerted on the roller coaster through the chain?

1. 510 N

2. 205 N

3. 120 N

4. 335 N

5. 80 N

3. A runner runs three-quarters of the way around a circular track, of radius 60.0 m, while she collides with another runner and trips. (a) How far had the runner travelled on the track before the collision? (b) What was the magnitude of the displacement of the runner from her starting position while accident occurred?

(a) 265 m (b) 93.4 m

(a) 278 m (b) 86.8 m

(a) 292 m (b) 78.6 m

(a) 283 m (b) 84.9 m

4. An arrow is shot into the air at an angle of 60.0° above the horizontal with the speed of 20.0 m/s. (a) what are the x- and y-components of the velocity of the arrow 3 s after it leaves the bowstring? (b) What is the displacement of the arrow in the y-direction throughout the 3.0-s interval?

6. A highway curve has a radius of 122 m. At what angle must the road be banked so that a car travelling at 26.8 m/s (60 mph) has no tendency to skid sideways on road? [Hint: No tendency to skid means the frictional force is zero.]

1. 25°

2. 22°

3. 31°

4. 38°

7. A small body of mass 0.5kg is attached by a 0.50m long cord to a pin set into the surface of a frictionless table top. The body moves in a circle on the horizontal surface with the speed of 2.0π m/s. (a) what is the magnitude of the centripetal acceleration of the body? (b) What is the tension in the cord?

(a) 79 m/s2 ; (b) 37 N

(a) 79 m/s2 ; (b) 39 N

(a) 65 m/s2 ; (b) 33 N

(a) 65 m/s2 ; (b) 37 N

(a) 79 m/s2 ; (b) 33 N

8. The tension in the horizontal (? =0) towrope pulling a water-skier is 240 N while the skier moves due west a distance of 54m. How much work does towrope do on the water-skier?

1. 10 kJ

2. 4.4 kJ

3. 18 kJ

4. 13 kJ

9. A roller coaster car (mass = 988 kg including passengers) is about to roll down a track (the figure below). The diameter of the circular loop is 20m and the car starts out from rest 40m above the lowest point of the track. Overlook friction and air resistance and assume g = 9.81 m/s2. (a) At what speed does the car reach the top of loop?

(a) 11.4 m/s

(a) 21.6 m/s

(a) 12.9 m/s

(a) 9.9 m/s

(a) 19.8 m/s

10. A sports car travelling along a straight line increases its velocity from 20.0 mi/h to 60.0 mi/h. What is the ratio of the final to the initial magnitude of its momentum?

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